REGULATION OF CELLULAR EXCITABILITY BY STRESS HORMONES

描述：(改编自《调查者摘要》) 申请人最近提出的证据表明，人的内在兴奋性 嗜铬细胞受应激激素的调节 下丘脑-垂体-肾上腺轴。拟议的研究将进一步测试和 测量将应力轴与急性期力学联系起来的机制 肾上腺素反应。证据表明，类固醇应激激素 控制一个关键离子通道的组装，BK型钾通道。通过 偏向于前信使RNA的选择性剪接，荷尔蒙“调节” 渠道的结构，以增加渠道的易用性 打开了。这会增加细胞的兴奋性和肾上腺素 分泌物。本研究将使用分子生物学(RT-PCR和 免疫细胞化学)和电生理(膜片钳)技术 平行测量应激激素对心脏结构和功能的影响 BK频道。体内和体外的手术和荷尔蒙扰动将 确定调控信号转导的分子途径，以及 探索对细胞功能的影响。这项研究得益于这一事实 同样的分析方法也可以用来比较牛和鼠的细胞， 具有不同应激反应谱的大鼠品系之间以及大鼠之间 发育阶段，除了试验性治疗组之间。 因此，我们的目标是阐明应激的分子机制 经历、生命阶段和基因适应和/或限制了 儿茶酚胺分泌物。

DESCRIPTION: (Adapted from the Investigator's Abstract) The applicant recently presented evidence that the intrinsic excitability of chromaffin cells is regulated by stress hormones of the hypothalamic-pituitary-adrenal axis. The proposed study will further test and measure the mechanism linking the stress axis to the mechanics of acute epinephrine responses. The evidence suggests that steroid stress hormones control the assembly of a key ion channel, the BK-type potassium channel. By biasing the alternative splicing of pre-messenger RNA, the hormones "tune" the channel's structure in a way that increases the ease with which the channel is opened. This results in an increase in the cell's excitability and epinephrine secretion. This study will use molecular biological (RT-PCR and immunocytochemistry) and electrophysiological (patch clamp) techniques in parallel to measure the effects of stress hormones on structure and function of the BK channel. Surgical and hormonal perturbations in vivo and in vitro will identify molecular pathways by which the regulatory signal is transduced, and explore the consequences to cell function. The study benefits from the fact that the same assays can be applied to compare between bovine and rat cells, between rat strains with different stress response profiles, and between rat developmental stages, in addition to between experimental treatment groups. Thus, the goal is to elucidate molecular mechanisms by which stress experiences, life stages, and genes adapt and/or limit the mechanisms of catecholamine secretion.